There have been theories suggesting antimatter might go up. However, Albert Einstein, in his General Theory of Relativity, postulated over a century ago that antimatter should act like regular matter and fall. Now, CERN scientists have reaffirmed with high certainty that Einstein’s theory was correct, and antimatter really falls down.
They’ve verified how antimatter, matter’s equivalent, reacts to gravity. The results have been published in Nature.
There was a long-unresolved debate among physicists about antimatter’s response to gravity.
- Einstein’s general theory of relativity suggested that antimatter, like matter, would fall.
- However, some physicists proposed that antimatter should rise upward.
- Current experiments at CERN have conclusively demonstrated that antimatter does indeed fall.
- This discovery supports another facet of the general theory.
- Einstein’s general theory was published in 1915, before the discovery of antimatter in 1932.
- The theory views all matter as the same, suggesting a common gravitational response.
- Therefore, both matter and antimatter are expected to react similarly to gravitational forces.
What Is Antimatter?
- Antimatter is essentially the reverse of matter.
- Where matter has negatively charged electrons orbiting atomic nuclei, antimatter has positively charged counterparts called positrons.
- Similarly, while protons exist inside matter’s atomic nuclei, their opposite in antimatter are antiprotons.
- According to theories about the Big Bang, the creation of the universe resulted in equal amounts of matter and antimatter.
- Both matter and antimatter are alike in most respects.
- However, when matter and antimatter meet, they destroy each other, converting their combined mass into energy.
The ALPHA Collaboration
- The ALPHA Collaboration at CERN focuses on studying antimatter due to its scarcity in the universe compared to regular matter.
- This makes it challenging to investigate the effects of gravity on antimatter.
- They conduct these studies in the Antimatter Factory, a facility within CERN that produces antihydrogen atoms.
- A hydrogen atom is made up of a single electron orbiting a nucleus containing a single proton.
- Conversely, an antihydrogen atom comprises a single positron, orbiting a nucleus with a single antiproton.
- After forming antiprotons and positrons into antihydrogen atoms, the Antimatter Factory traps them.
- This trapping prevents the antihydrogen atoms from interacting with regular matter, as they would destroy each other upon contact.
- A test was conducted with the magnetic field turned off to ensure the annihilation of antimatter.
- A device known as ALPHA-g, introduced in 2021, tracked the vertical points of annihilation.
- Scientists trapped around 100 antihydrogen atoms in groups and then gradually released these atoms over a 20-second interval.
- The results from this experiment were contrasted with outcomes the researchers would have expected from an identical test using standard matter.
- According to computer models, 20% of the matter atoms would have escaped from the trap’s top and the remaining 80% from the bottom.
- This difference is attributed to gravity, leading to the majority of matter atoms dropping downwards.
- The study involved multiple releases of antihydrogen atom groups, each containing 100 atoms.
- The researchers averaged the data from seven different releases.
- The findings confirmed that antimatter atoms behave similarly to matter atoms when subjected to gravity.
- This implies that both matter and antimatter fall under the influence of gravity in the same way.
- Jeffrey Hangst, the spokesperson for ALPHA, highlighted that it took them 30 years to create and control the anti-atom.
- Hangst further emphasised that the anti-atom had to be controlled well enough to observe its response to gravitational force.
What Next?
Though antimatter doesn’t go up, it may not fall down at the same pace as matter. The research team plans to enhance their experiment for greater sensitivity. This will help determine if the antimatter’s fall rate varies slightly. If a difference exists, it could solve the major mystery of the Universe’s origin.